<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var year = prompt('请输入年份：')
        if (year % 4 == 0 && year % 100 != 0 || year % 400 ==0 ) {
            alert('您输入的年份是闰年')
        } else {
            alert('您输入的年份是平年')
        }
    </script>
</body>
</html>